Washington — The controversy over access to contraception first sparked by President Obama’s health-care law is now moving to Congress.

Republicans are trying to add an amendment to a highway bill currently in the Senate that would allow employers to opt out of a new federal health-care mandate for their employees if they have religious objections. The Senate is expected to vote Thursday morning.

A recently announced rule in the health care law would have forced businesses including those affiliated to the Catholic Church to provide health-care options that included access to contraception – something the Catholic Church opposes. Mr. Obama has offered a compromise on the rule, but conservatives say it doesn't go far enough.

Senate Democrats – also with exceptions – see the issue as a war on women and a deliberate bid to obstruct passage of a long-delayed bill that would fund major construction and repair projects, affecting millions of jobs.

The issue goes to the heart of the culture wars, also roiling the GOP presidential primary.

“This issue gets right at the heart of who we are as a people,” said Senate minority leader Mitch McConnell (R) of Kentucky, in an opening floor speech on Thursday. “It is not in the power of the federal government to tell anybody what to believe or to punish them for practicing those beliefs,” he added.

But Democrats say the highway bill shouldn’t become a venue for the contraception issue.

“This legislation is too important to be bogged down by political amendments,” said Senate majority leader Harry Reid (D) of Nevada in a floor speech on Thursday.

Democrats say the Blunt measure is overly broad and would allow employers to block a wide variety of healthcare services on the grounds of a vague heading of “religious beliefs and moral convictions” that could be extended to deny a wide range of services.

It also takes a chisel to President Obama’s signature health-care law at the expense of a highway bill that promises to protect 1.8 million construction jobs and create millions more, they add.

“It is the biggest jobs bill that we will move in the remaining time in this Congress. Don’t muck it up with extraneous amendments particularly that go after women’s health,” said Sen. Barbara Boxer (D) of California at a briefing with reporters on Wednesday.

Republicans call the health argument a misrepresentation of their views. “I regret that this issue has been reframed for political purposes into a woman’s right to choose,” says Sen. Dan Coats (R) of Indiana.

Senator Blunt says that his amendment simply extends the same “conscience protection language” that has been part of US law for nearly 40 years, endorsed in the past by many of the Democrats not opposing it.

“The reason we’re debating this now is that the [Obama] administration issued an order that is just unprecedented,” he said from the floor before Thursday’s vote.

More than 60 percent of Americans say they are aware of the dispute, according to the Pew Research Center for the People & the Press. Some 48 percent favor an exemption for church-affiliated schools and hospitals, and 44 percent say they should provide the same health coverage as other employers.

A recent CBS News/New York Times poll finds that 61 percent of Americans favor the president’s mandate, while 31 percent oppose it.